A plan to seek a judicial review over a controversial man-made beach project was thrown into uncertainty after environment officials refused to provide details on the project in time.

Six weeks have passed since a coalition of green groups wrote to the Environmental Protection Department, urging it to review the Lung Mei beach plan in Tolo Harbour and withdraw its work permit. The department was expected to reply by today.

But undersecretary for environment Christine Loh Kung-wai said yesterday the government could not respond in time.

"The Department of Justice is looking at the materials submitted by the groups. It is also gathering information to form a legal opinion. Six weeks is not enough," Loh said.

Initiated by Tai Po District Council a decade ago, the project is being opposed by environmentalists, who fear the 200-metre beach will wipe out more than 200 marine species. Although the project was passed by the Advisory Council on the Environment and the Legislative Council, the coalition accused the government of misleading the two bodies and the public into believing there was no alternative for a beach in New Territories East.

They said officials had not looked into the options of the natural sandy coasts at Wu Kai Sha and To Tau Wan. The groups warned they would mount a legal challenge if officials refused to withdraw the permit.

Peter Li Siu-man, campaign manager of the Conservancy Association, which is a member of the coalition, said he hoped the government would give a date for its reply.

He said: "We have not given up the judicial review idea and our lawyers are looking at it."

To appease opponents, Loh said in October she would engage green groups and experts to work out a "Ting Kok Plus" plan to conserve the rest of the Tolo Harbour. She led a meeting yesterday with 29 people, including professors and green groups - but not including the coalition - to discuss "an authoritative conservation research".